Effect of priming guava seeds with H2O2 on seedling production under salt stress

Guava is one of the most economically important fruit crops grown in the Northeast region of Brazil. This region is characterized by a high concentration of salts in the water sources used for irrigation, necessitating the development of strategies to minimize the harmful effects of salt stress on production systems. The objective of this study was to analyze the effect of priming guava seeds with H2O2 on seedling production under salt stress. The experiment was conducted in a greenhouse at the Center for Agri-food Science and Technology at the Federal University of Campina Grande, located in Pombal, PB, Brazil. A randomized complete block experimental design was employed, involving a 5 × 3 factorial arrangement represented by five levels of electrical conductivity of irrigation water (ECw: 0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1) and three concentrations of hydrogen peroxide (H2O2: 0, 25, and 50 µM). Four replications were used, with five plants per plot. Salinity in the water starting from 0.3 dS m-1 reduced growth, relative water content, photosynthetic pigments, dry biomass, and Dickson’s quality index, and increased the water saturation deficit in ‘Paluma’ guava seedlings 110 days after sowing. Hydrogen peroxide at a concentration of 25 µM increased the emergence speed index of seedlings, although its application at a concentration of up to 50 µM did not alleviate the adverse impacts of salt stress on ‘Paluma’ guava seedlings under an electrical conductivity of irrigation water of 3.5 dS m-1.